/*
  将下面异步代码使用 Promise 的方法改进
  尽量用看上去像同步代码的方式
  setTimeout(function () {
    var a = 'hello'
    setTimeout(function () {
      var b = 'lagou'
      setTimeout(function () {
        var c = 'I ♥ U'
        console.log(a + b +c)
      }, 10)
    }, 10)
  }, 10)
*/


function fn() {
    
    return new Promise((resolve, reject) => {
        var a = 'hello';
        resolve(a);
    })
}

fn()
    .then(res => {
        var b = 'lagou';
        return res + b;
    })
    .then(res => {
        var c = 'I ♥ U';
        console.log(res+c);
    })
